Organosilicon compounds, preparation method and uses thereof

ABSTRACT

The invention concerns organosilicon compounds, their method of preparation and their use as coupling agents for depositing, at the surface of a solid support, an organised self-assembled monolayer. The invention also concerns a method for obtaining solid supports whereof the surface is modified by an organised self-assembled monolayer comprising a system of said organosilicon compounds, and the use of said solid supports for biomolecular synthesis or immobilisation.

[0001] The present invention relates to organosilicon compounds, totheir process of preparation and to their use in depositing aself-assembled monolayer of these compounds at the surface of a solidsupport. The present invention also relates to the solid supports thusmodified and to their process of preparation, in addition to their usein the synthesis or immobilization of biomolecules.

[0002] An organized self-assembled monolayer (SAM) is defined as anassemblage of molecules in which the molecules are organized, whichorganization is due to interactions between the chains of the molecules,giving rise to a stable, monomolecular and well-ordered anisotropic film(A. Ulman, Chem. Rev., 1996, 96, 1533-1554).

[0003] These self-assembled monolayers, which can be obtainedreproducibly (J. B. Brozska et al., Langmuir, 1994, 10, 4367-4373), havethe distinguishing feature of forming a dense and homogeneous film whichis resistant to chemical treatments (acidic or basic).

[0004] The formation of SAM on solid supports, for example usingoctadecyltrichlorosilane, makes possible the preparation of homogeneousorganic surfaces with well defined parameters, both chemically andstructurally. These surfaces can act as two-dimensional models forfundamental studies, in particular as regards self-assembling phenomenaand the chemistry of interfaces (A. Ulman, ibid).

[0005] Various organosilicon compounds have been used as coupling agentsfor the functionalization of solid supports (L. A. Chrisey et al.,Nucleic Acids Research, 1996, 24, 15, 3031-3039, U. Maskos et al.,Nucleic Acids Research, 1992, 20, 7, 1679-1684) with the aim ofimmobilizing oligonucleotides or of synthesizing them in situ. However,the organosilicon coupling agents used in these studies formnonhomogeneous films which have very little resistance to the subsequentchemical treatments for the synthesis or immobilization ofoligonucleotides. Furthermore, the formation of the films with thesecoupling agents is not reproducible.

[0006] The Inventors thus set themselves the aim of overcoming thedisadvantages of the prior art and of providing for coupling agentswhich make it possible to obtain true SAMs at the surface of solidsupports, namely stable monolayer films in which the molecules areself-assembled and organized. The Inventors also set themselves the aimof providing for coupling agents which can be reproducibly grafted tosolid supports, while rendering possible syntheses or immobilizations ofbiomolecules at the surface of the monolayer formed on the support.

[0007] A subject matter of the present invention is organosiliconcompounds of formula (I)

[0008] in which:

[0009] n is between 15 and 35, preferably between 20 and 25,

[0010] k is between 0 and 100, preferably between 0 and 5,

[0011] i is an integer greater than or equal to 0, preferably equal to 0or to 1,

[0012] X₁, X₂ and X₃, which can be identical to or different from oneanother, are selected from the group consisting of saturated, linear orbranched, C₁ to C₆ alkyls and hydrolyzable groups, at least one from X₁,X₂ or X₃ representing a hydrolyzable group, and

[0013] if k=0 and i=0, then Z represents an R₁ group,

[0014] if k=0 and i≧1, then Z represents an —OR₁, —OCOR₁, —NR₁R₂,—COOR₁, —CONR₁R₂ or —SR₁ group or a halogen atom,

[0015] if k≧1 and i=0, then Z represents an —R₁, —COR₁, —COOR₁,—CONR₁R₂, —CF₃ or —(CF2)_(j)CF₃ group, j being between 1 and 10,

[0016] if k≧1 and i≧1, then Z represents an —OR_(1, —OCOR) ₁, —NR₁R₂,—COOR₁, —CONR₁R₂, —SR₁, —CF₃ or —(CF₂)_(j)CF₃ group, j being as definedabove, or a halogen atom,

[0017] R₁ and R₂, which can be identical or different, represent ahydrogen atom, an optionally substituted, saturated or unsaturated andlinear or branched hydrocarbonaceous chain comprising from 1 to 24carbon atoms, or an aromatic group, provided that, when k=i=0 and n=15,R₁ is other than the —CH₂CF₃ group and, when k=i=0 and n=19, R₁ is otherthan the —(CH₂)₆—C≡C—C≡CH group.

[0018] When Z represents an —OR₁, —OCOR₁ or —COOR₁, group, irrespectiveof the values of i, and when k≧1, then it is clearly understood that Zcan represent any group resulting from the protection of a hydroxyl orcarboxylic acid functional group, such as the protective groupsdescribed in Protective groups in organic synthesis (T. W. Greene etal., 2nd edition, Wiley Interscience), for example a cyclic protectivegroup.

[0019] Within the meaning of the present invention, the term “aromatic”is understood to mean any group which has one or more aryl rings, forexample a phenyl ring. The term “hydrolyzable group” is understood tomean any group capable of reacting with an acid in an aqueous medium soas to give the compounds X₁H, X₂H or X₃H.

[0020] Preferably, said hydrolyzable group is selected from the groupconsisting of halogen atoms, the —N(CH₃)₂ group and —OR groups, R beinga saturated, linear or branched, C₁ to C₆ alkyl group.

[0021] As regards the Z groups and the hydrolyzable groups, suitablehalogen atoms are just as easily fluorine as chlorine, bromine oriodine.

[0022] The organosilicon compounds according to the present inventionadvantageously exhibit highly varied functionalities, in view of thediversity of the end Z groups which can be used, it being possible forthese Z groups to be modified and functionalized as desired according toorganic chemistry reactions well known to a person skilled in the art.

[0023] According to an advantageous embodiment, a compound of formula(I) is such that X₁, X₂ and X₃ represent chlorine atoms, n is equal to22, i is equal to 0, k is equal to 1 or to 3 and Z represents a —COCH₃group.

[0024] According to another advantageous embodiment, a compound offormula (I) is such that X₁, X₂ and X₃ represent chlorine atoms, n isequal to 22, i is equal to 1, k is equal to 2 and Z represents a —COOCH₃group.

[0025] Surprisingly, the products selected indeed make it possible toobtain true SAMs at the surface of solid supports, namely stablemonolayer films in which the molecules are self-assembled and organized.

[0026] Another subject matter of the present invention is a process forthe preparation of the compounds of formula (I) described above in whichi is other than 1, which process comprises the following stages:

[0027] a) preparation of an unsaturated precursor of formula (III)

[0028]  by reaction of a diol of formula HO—(CH₂—CH₂—O)_(k)—H with anunsaturated compound of formula (II):

[0029]  in which Y represents a nucleofuge group and n and k are asdefined above in connection with the formula (I);

[0030] b) production, by functionalization of the hydroxyl end of thecompound of formula (III), of an unsaturated precursor of formula (IV):

[0031]  in which Z and i are as defined above in connection with theformula (I);

[0032] c) production, by hydrosilylation of the unsaturated precursor offormula (IV) using a hydrosilane of formula HSiX₁X₂X₃, of a siliconcompound of formula (I):

[0033]  in which at least one from X₁, X₂ and X₃ represents a halogenatom; and

[0034] d) optionally, production of another compound of formula (I) bysubstitution of one or more of the X₁, X₂ and X₃ groups of the compoundobtained in stage c) using X₁, X₂ and/or X₃ groups as defined inconnection with the compound of formula (I) according to the presentinvention.

[0035] Stage b) of functionalization of the hydroxyl end of the compoundof formula (III) can, for example, be carried out, when i is equal to 0,by an esterification reaction using alkyl chloride when Z represents a—COR₁ group, R₁ being as defined in connection with the compound offormula (I) according to the invention.

[0036] Another subject matter of the present invention is a process forthe preparation of the compounds of formula (I) according to the presentinvention as described above in which i is equal to 1, which processcomprises the following stages:

[0037] a) preparation of an unsaturated precursor of formula (III′):

[0038]  by reaction of an unsaturated compound of formula (II) asdefined above with a diol of formula HO—(CH₂—CH₂—O)_(k+1)—H, n and kbeing as defined above in connection with the compound of formula (I)according to the present invention;

[0039] b) production, by oxidation of the hydroxyl end of the compound(III′), of an unsaturated precursor of formula (IV′):

[0040]  in which Z represents a carboxylic acid functional group;

[0041] c) optionally, functionalization of the carboxylic acid end ofthe compound of formula (IV′) using another Z group as defined inconnection with the formula (I) of the compounds according to thepresent invention;

[0042] d) production, by hydrosilylation of the unsaturated precursor offormula (IV′) using a hydrosilane of formula HSiX₁X₂X₃, of a siliconcompound of formula (I):

[0043]  in which at least one from X₁, X₂ and X₃ represents a halogenatom; and

[0044] e) optionally, production of another compound of formula (I) bysubstitution of one or more of the X₁, X₂ and X₃ groups of the compoundobtained in stage d) using X₁, X₂ and/or X₃ groups as defined inconnection with the compound of formula (I) according to the presentinvention.

[0045] In the processes described above for the preparation of thecompounds of formula (I) according to the invention, whatever the valueof i, stage a) is advantageously carried out in a polar solvent, forexample water or tetrahydrofuran, in a basic medium and at the refluxtemperature of the solvent; use may be made, as nucleofuge group Ypresent in the compound of formula (II), of, for example, a halogen atomor a tosyl group; furthermore, the stage of hydrosilylation of theunsaturated precursor can be carried out in the presence oftrichlorosilane.

[0046] The organosilicon compounds of formula (I) according to thepresent invention can, for example, be used in sol-gel processes, thatis to say be hydrolyzed and then crosslinked so as to obtain novelmaterials, or alternatively can act as comonomers in syntheses of novelpolymers with the aim of modifying the chemical and mechanicalproperties of these polymers through the functionalities introduced, forexample in the form of pendent chains. They can also be used to form anorganized self-assembled monolayer at the surface of a solid support.

[0047] Thus, another subject matter of the present invention is the useof an organosilicon compound of general formula (I′):

[0048] in which:

[0049] n is between 15 and 35,

[0050] k is between 0 and 100,

[0051] i is an integer greater than or equal to 0,

[0052] X₁, X₂ and X₃, which can be identical to or different from oneanother, are selected from the group consisting of saturated, linear orbranched, C₁ to C₆ alkyls and hydrolyzable groups, at least one from X₁,X₂ or X₃ representing a hydrolyzable group, and

[0053] if k=0 and i=0, then Z represents an R₁ group,

[0054] if k=0 and i≧1, then Z represents an —OR₁, —OCOR₁, —NR₁R₂,—COOR₁, —CONR₁R₂ or —SR₁ group or a halogen atom,

[0055] if k≧1 and i=0, then Z represents an —R₁, —COR₁, —COOR₁,—CONR₁R₂, —CF₃ or —(CF₂)_(j)CF₃ group, j being between 1 and 10,

[0056] if k≧1 and i≧1, then Z represents an —OR₁, —OCOR₁, —NR₁R₂,—COOR₁, —CONR₁R₂, —SR₁, —CF₃ or —(CF₂)_(j)CF₃ group, j being as definedabove, or a halogen atom,

[0057] R₁ and R₂, which can be identical or different, represent ahydrogen atom, an optionally substituted, saturated or unsaturated andlinear or branched hydrocarbonaceous chain comprising from 1 to 24carbon atoms, or an aromatic group,

[0058] to form, at the surface of a solid support, an organizedself-assembled monolayer.

[0059] The use of the organosilicon compounds of general formula (I′)makes it possible to advantageously modify the surface of solid supportsby a dense and organized monolayer which corresponds to the definitionof the SAMs given above. The monolayer thus formed on the surfaceexhibits high resistance with respect to chemical treatments (acidic orbasic). The robustness and homogeneity of the monolayer formed at thesurface of the support by the organosilicon agents according to thepresent invention make it possible, for example, to treat supportsagainst corrosion.

[0060] The compounds grafted to the support give rise to strong covalentbonds of siloxane type with the surface and develop strong cohesionbetween their alkyl chains, the result of a self-assembling of themolecules, which protects the siloxane bonds. In addition, the graftingis reproducible and the Z groups of the grafted compounds exhibit highchemical reactivity.

[0061] Another subject matter of the present invention is a solidsupport, the surface of which is modified by an organized self-assembledmonolayer, characterized in that said monolayer comprises a network ofat least one organosilicon compound of general formula (I′) as definedabove.

[0062] Within the meaning of the present invention, the term “network”is understood to mean an assemblage of molecules in which the moleculesare organized and in which the chains of the molecules interact with oneanother via covalent bonds or noncovalent bonds (for example, Van derWaals forces).

[0063] It is clearly understood that said monolayer, in addition to theorganosilicon compounds of general formula (I′) according to the presentinvention, can also comprise any other type of compound capable of beinggrafted to the solid support (production of a “mixed” monolayer), whichmakes it possible to reduce the density of the compounds of formula (I′)on the support, when such an effect is desired.

[0064] Suitable solid supports are those possessing a hydrated surface.Preferably, said solid support is such that its surface exhibits, beforebeing modified, hydroxyl groups. It is advantageously selected from thegroup consisting of glasses, ceramics (preferably of oxide type), metals(for example, aluminum or gold) and semimetals (such as oxidizedsilicon).

[0065] Another subject matter of the present invention is a process forthe production of a solid support as defined above, characterized inthat it comprises the following stages:

[0066] a) removal of contaminants from a solid support and hydrationand/or hydroxylation of its surface,

[0067] b) introduction, under an inert atmosphere, of at least oneorganosilicon compound of general formula (I′) as defined above into amixture of at least two solvents comprising at least one nonpolarhydrocarbonaceous solvent,

[0068] c) silanization of the support obtained in stage a) by immersionin the solution prepared in stage b), and

[0069] d) rinsing of the modified support obtained in stage c) using asolvent, preferably a polar solvent.

[0070] The term “contaminant” of the solid support is understood to meanany compound, such as grease, dust or other compounds, present at thesurface of the support and which does not form part of the chemicalstructure of the support itself.

[0071] The process according to the invention makes it possibleadvantageously to chemically modify the properties of an inorganicsurface, this being achieved as a function of the Z groups introduced bythe organosilicon compounds grafted to the surface.

[0072] In a particularly advantageous way, according to the nature ofthe solid support, stage a) is carried out using one or more solventsand/or oxidizing agents and/or hydroxylating agents (for example, achromium(VI)/sulfuric acid mixture), a detergent (for example,Hellmanex®), a photochemical treatment with ozone or any otherappropriate treatment.

[0073] Stage b) can advantageously be carried out in a mixture of atleast one nonpolar hydrocarbonaceous solvent and of at least one polarsolvent. In this case, the proportions by volume of the nonpolar solventwith respect to the polar solvent are preferably between 70/30 and 95/5.By way of examples and without implied limitation, a nonpolarhydrocarbonaceous solvent which can be used is cyclohexane and a polarsolvent which can be used is chloroform.

[0074] The concentration of the organosilicon compound in the mixture ofsolvents, in stage b) of the process according to the present invention,is advantageously between 1×10⁻⁵ and 1×10⁻² mol/liter.

[0075] Stage c) of silanization of the support can be carried out for atime of between 1 minute and 3 days and at a temperature of between −10°C. and 120° C., according to the solvents used.

[0076] The solid supports, the surfaces of which are modified by anorganized self-assembled monolayer according to the present invention,can advantageously be used, as a function of the nature of the Zterminal group, as supports for the synthesis or the immobilization ofbiomolecules, for example oligonucleotides or proteins.

[0077] Thus, another subject matter of the present invention is the useof a solid support as described above in the synthesis or theimmobilization of biomolecules via covalent bonding.

[0078] A more particular subject matter of the present invention is aprocess for the synthesis of biomolecules on a solid support asdescribed above, characterized in that said biomolecules are composed ofa sequence of repeat units and in that said process comprises successivestages of grafting said repeat units, the first grafted repeat unitcarrying a functional group which is reactive with respect to the Zgroups of the organosilicon compounds present on the solid support.

[0079] An additional subject matter of the present invention is aprocess for the immobilization of biomolecules on a solid support asdescribed above, characterized in that it comprises a stage of graftingsaid biomolecules which carry functional groups which are reactive withrespect to the Z groups of the organosilicon compounds, to said solidsupport.

[0080] Before carrying out the processes for the synthesis orimmobilization of biomolecules described above, and in the case wherethe Z terminal functional group of the organosilicon compounds is, forexample, an —OCOR₁ group (in which R₁ is as defined in connection withthe formula (I′) of the compounds according to the present invention) ora —COOR₁ group (in which R₁ is as defined in connection with the formula(I′) of the compounds according to the present invention but is otherthan a hydrogen atom), the corresponding alcohol or carboxylic acidfunctional group can be deprotected beforehand, if necessary, by anappropriate chemical treatment, such as 0.5M potassium hydroxide in awater/ethanol mixture.

[0081] In addition to the applications which have just been mentionedabove, the solid supports according to the present invention can also beused, by way of examples and without implied limitation, to graftcatalysts to inorganic supports or, in the field of combinatorialchemistry, to carry out varied chemical syntheses on solid supports.They can also be subjected to subsequent chemical modifications: forexample, treatment with amines of a solid support to which brominatedorganosilicon compounds according to the present invention are graftedmakes it possible to obtain a surface with biocidal properties.

[0082] In addition to the preceding arrangements, the invention alsocomprises other arrangements which will emerge from the descriptionwhich will follow, which description refers to examples of the synthesisof organosilicon compounds according to the present invention and of themodification of solid supports by an organized self-assembled monolayerof these organosilicon compounds, as well as to the appended drawings,in which:

[0083]FIGS. 1, 2 and 3 illustrate the synthesis of unsaturatedprecursors of the organosilicon compounds according to the presentinvention,

[0084]FIG. 4 illustrates the silylation of these unsaturated precursors,

[0085]FIG. 5 represents infrared spectra obtained after threeexperiments of grafting the organosilicon compound 14 to Au/Si/SiO₂substrates, and

[0086]FIG. 6a represents the density, analyzed by Raman spectroscopy, ofthe surface of the Au/Si/SiO₂ substrate to which the organosiliconcompounds 14 are grafted; FIGS. 6b and 6c represent the Raman spectrataken at two different points of this surface.

[0087] It must be clearly understood, however, that these examples aregiven solely by way of illustration of the subject matter of theinvention, of which they do not in any way constitute a limitation.

EXAMPLE 1 Synthesis of Organosilicon Compounds of Formula (I)

[0088] 1) Synthesis of an Unsaturated Alcohol (FIG. 1)

[0089] Preparation of the Magnesium Derivative 2

[0090] Magnesium (1.8 g, 70 mmol) is introduced into a 500 mlthree-necked round-bottomed flask under an inert atmosphere. Theunsaturated brominated derivative 1 (16.3 g, 70 mmol), dissolvedbeforehand in 70 ml of anhydrous THF (tetrahydrofuran), is addeddropwise. A few drops of dibromoethane may be necessary to activate themagnesium. The reaction mixture is brought to reflux for 1 h 30 in orderto obtain the magnesium derivative 2, which will be used immediately.

[0091] Preparation of the Lithium Alkoxide 4

[0092] The bromoalcohol 3 (17.7 g, 70 mmol, 1 eq) is dissolved in 70 mlof anhydrous THF in a dry 250 ml three-necked round-bottomed flask underan inert atmosphere. The solution is cooled to −78° C. and thenmethyllithium (50 ml, 80 mmol, 1.1 eq) is added dropwise. The lithiumalkoxide 4 is obtained.

[0093] Preparation of the Unsaturated Alcohol 5

[0094] The magnesium derivative 2 is cooled to −78° C. and then copperiodide (1.1 g, 3.5 mmol, 0.05 eq) is added. The solution is stirred for25 minutes at −78° C. and then reheated to ambient temperature until acrimson color is obtained. The solution is then immediately cooled to−78° C. and the lithium alkoxide 4 is introduced using a hollow needleunder an argon atmosphere. The solution is stirred for 1 h at −78° C.and then for 18 h at ambient temperature. The excess methyllithium isdestroyed by addition of ethanol, followed by hydrolysis in an acidicmedium by addition of a 10% aqueous hydrochloric acid solution. Theorganic phase is extracted three times with diethyl ether. The etherealphases are combined and washed with a 10% hydrochloric acid solution,with water and finally with a saturated aqueous NaHCO₃ solution. Theorganic phase is subsequently washed to neutrality, dried over MgSO₄ andthen concentrated under vacuum. The product is purified byreprecipitation from acetone. The compound 5 is obtained in the form ofa white solid (19.8 g; melting point of 61.7-62.8° C.; yield of 87%).Its analysis by infrared and proton and carbon-13 NMR is as follows.

[0095] IR (ν(cm⁻¹)): 3330, 3079, 2919, 2851, 1642

[0096]¹H NMR (CDCl₃, δ (ppm)): 6.0-5.7 (m, 1 H), 5.1-4.7 (m, 2 H); 3.6(t, 2 H), 2.2-1.9 (m, 2 H) and 1.7-1.2 (m, 37 H, including 1 Hexchangeable with D₂O).

[0097]¹³C NMR (CDCl₃, δ (ppm)): 139.3, 113.8, 62.8, 33.6-25.8 (19 CH₂).

[0098] 2) Introduction of an Ethylene Glycol (FIG. 2)

[0099] Synthesis of the Unsaturated Chlorinated Derivative 6

[0100] The alcohol 5 obtained above (15 g, 46 mmol, 1 eq) and pyridine(40.36 ml, 6 mmol, 0.1 eq) are introduced into a 250 ml two-neckedround-bottomed flask equipped with a mechanical stirrer and surmountedby a vertical reflux condenser. Thionyl chloride (6 ml, 70 mmol, 1.5 eq)is then added dropwise. The reaction medium is stirred for 1 h and isthen brought to reflux until the OH band has completely disappeared(monitored by infrared spectroscopy). The reaction medium issubsequently hydrolyzed and then extracted three times with diethylether. The ethereal phases are combined and washed with a 10%hydrochloric acid solution, with water and then with a saturated NaHCO₃solution. The ethereal phase is subsequently washed to neutrality, driedover MgSO₄ and concentrated under vacuum. The compound 6 is obtained inthe form of a yellow solid and is then purified by silica chromatography(eluent: petroleum ether/ether, 70/30 v/v); a white solid is obtained(14 g; melting point of 34.1-34.9° C.; yield of 75%). Its analysis byinfrared and proton and carbon-13 NMR is as follows.

[0101] IR(dispersion in KBr) ν (cm⁻¹): 3076, 2917, 2849, 1641.

[0102]¹H NMR (CDCl₃, δ (ppm)): 6.0-5.7 (m, 1 H), 5.1-4.7 (m, 2 H),3.5-3.3 (t, 2 H), 2.2-1.9 (m, 2 H) and 1.7-1.2 (m, 36 H).

[0103]¹³C NMR (CDCl₃, δ (ppm)): 139.2, 113.8, 33.8-25.6 (20 CH₂)

[0104] Synthesis of the Unsaturated Iodinated Derivative 7

[0105] The unsaturated chlorinated compound 6 (10.6 g, 32 mmol) andsodium iodide (22 g, 140 mmol, 4 eq) are dissolved in acetone (40 ml) ina 250 ml round-bottomed flask. The solution is then brought to refluxfor 18 h. The reaction medium is subsequently extracted with diethylether and the ethereal phases are combined, then washed with water,dried over MgSO₄ and concentrated under vacuum. The product is purifiedby precipitation operations from acetone. The compound 7 is obtained inthe form of a yellow solid (11 g; melting point of 41.1-42.0° C.; yieldof 81%). Its analysis by infrared and proton and carbon-13 NMR is asfollows.

[0106] IR (dispersion in KBr) ν (cm⁻¹): 3076, 2917, 2849, 1641.

[0107]¹H NMR (CDCl₃, δ (ppm)): 6.0-5.7 (m, 1 H), 5.1-4.7 (m, 2 H),3.2-3.0 (t, 2 H), 2.2-1.9 (m, 2 H) and 1.7-1.2 (m, 36 H).

[0108]¹³C NMR (CDCl₃, δ (ppm)): 139.2, 113.8, 33.8-25.6 (20 CH₂)

[0109] Synthesis of the Unsaturated Alcohol 8

[0110] A solution of ethylene glycol (11.5 g, 180 mmol, 10 eq) and ofsodium hydroxide (3.7 g, 90 mmol, 5 eq), reduced beforehand to a powder,in 20 ml of anhydrous THF is brought to reflux for 30 minutes. Theiodinated compound 7 (8 g, 18 mmol, 1 eq) and tetrabutylammoniumhydrogensulfate (0.62 g, 1.8 mmol, 0.1 eq) are added. The reactionmedium is subsequently brought to reflux for 72 h. After returning toambient temperature, an aqueous hydrochloric acid solution (10%, 50 ml)is introduced. The reaction medium is subsequently extracted three timeswith diethyl ether; the ethereal phases are combined and washed twicewith a 10% hydrochloric acid solution, with water and then with asaturated NaHCO₃ solution. The ethereal phase is subsequently washed toneutrality, dried over MgSO₄ and concentrated under vacuum. The solidobtained is reprecipitated from dichloromethane and then purified bysilica chromatography (eluent: dichloromethane/ethyl acetate; v/v:30/70). The compound 8 is obtained in the form of a white solid (1.4 g;melting point of 61.2-62.4° C.; yield of 21%). Its analysis by infraredand proton and carbon-13 NMR is as follows.

[0111] IR (dispersion in KBr) ν (cm⁻¹): 3330, 3080, 2917, 2849, 1643.

[0112]¹H NMR (CDCl₃, δ (ppm)): 6.0-5.7 (m, 1 H), 5.1-4.7 (m, 2 H),3.75-3.65 (m, 2 H), 3.55-3.4 (m, 4 H), 2.2-1.9 (m, 2 H) and 1.7-1.0 (m,37 H, including 1 H exchangeable with D₂O).

[0113]¹³C NMR (CDCl₃, δ (ppm)): 139.2, 113.8, 71.7 (2 CH₂), 63.7,33.6-25.8 (19 CH₂).

[0114] Synthesis of the Unsaturated Alcohol Protected in the Ester Form9

[0115] The unsaturated alcohol 8 (0.9 g, 2.7 mmol) is suspended indichloromethane (10 ml) and triethylamine (0.6 ml, 5.4 mmol, 2 eq) in a100 ml two-necked round-bottomed flask. The reaction medium is cooled to0° C. and then acetyl chloride (0.5 ml, 4 mmol, 1.5 eq) is addeddropwise using a syringe. The reaction medium is stirred for 15 minutesat 0° C. and then for 1 h 30 at ambient temperature. It is subsequentlyhydrolyzed and then extracted three times with diethyl ether. Theethereal phases are combined and washed with a 10% hydrochloric acidsolution, with water and then with a saturated NaHCO₃ solution. Theethereal phase is then washed to neutrality, dried over MgSO₄ andconcentrated under vacuum. The compound 9 is obtained in the form of awhite solid (0.9 g; yield of 100%). Its analysis by infrared and protonand carbon-13 NMR is as follows.

[0116] IR (dispersion in KBr) ν (cm⁻¹): 3080, 2917, 2849, 1742, 1643.

[0117]¹H NMR (CDCl₃, δ (ppm)): 6.0-5.7 (m, 1 H), 5.1-4.7 (m, 2 H),4.25-4.15 (m, 2 H), 3.60-3.50 (t, 2 H), 3.45-3.35 (t, 2 H), 2.2-1.9 (m,5 H) and 1.7-1.0 (m, 36 H).

[0118]¹³C NMR (CDCl₃, δ (ppm)): 172.0, 139.2, 113.8, 71.5, 68.5, 63.7,33.6-25.8 (19 CH₂), 21.0

[0119] 3) Introduction of Three Ethylene Glycol Units (FIG. 2)

[0120] Starting from the unsaturated iodinated derivative 7 obtainedabove and from triethylene glycol, an unsaturated alcohol 10 is obtainedand is then esterified to produce the product 11, this being carried outaccording to the same protocols as set out above.

[0121] The analysis of the product 10 by infrared and proton andcarbon-13 NMR is as follows.

[0122] IR (dispersion in KBr) ν (cm⁻¹): 3380, 3079, 2919, 2850, 1641.

[0123]¹H NMR (CDCl₃, δ (ppm)): 5.9-5.7 (m, 1 H), 5.1-4.7 (m, 2 H),4.3-4.2 (t, 2 H), 3.7-3.4 (m, 10 H), 3.4-3.3 (t, 2 H), 2.2-1.9 (m, 2 H)and 1.7-1.0 (m, 37 H, including 1 H exchangeable with D₂O).

[0124]¹³C NMR (CDCl₃, δ (ppm)): 139.3, 114.0, 71.6-68.2 (6 CH₂); 63.6,33.6-25.8 (19 CH₂).

[0125] The analysis of the product 11 by infrared and proton andcarbon-13 NMR is as follows.

[0126] IR (dispersion in KBr) ν (cm⁻¹): 3079, 2919, 2850, 1740, 1641.

[0127]¹H NMR (CDCl₃, δ (ppm)): 5.9-5.7 (m, 1 H), 5.1-4.7 (m, 2 H),4.3-4.2 (t, 2 H), 3.7-3.4 (m, 10 H), 3.4-3.3 (t, 2 H), 2.2-1.9 (m, 5 H)and 1.7-1.0 (m, 36 H).

[0128]¹³C NMR (CDCl₃, δ (ppm)): 171.5, 139.3, 114.0, 71.6-68.3 (6 CH₂),63.6, 33.6-25.8 (19 CH₂), 21.0.

[0129] 4) Preparation of the Unsaturated Esters (FIG. 3)

[0130] Starting from the unsaturated alcohol 10 obtained above, thecorresponding acid and the corresponding ester were prepared as follows.

[0131] Preparation of the Acid 12

[0132] The unsaturated alcohol 10 (3 g, 6.6 mmol) is suspended in 10 mlacetone in a 100 ml three-necked round-bottomed flask. 5 ml of 2M Jonesreagent (Bowden et al., J. Chem. Soc., 1946, 39) are added to thesuspension. The suspension is brought to reflux for 2 hours. Afterreturning to ambient temperature, the acetone is evaporated and thesolid is filtered off and then rinsed 5 times with water and 3 timeswith acetone cooled to 0° C. The solid is subsequently purified byrecrystallization from a THF/acetone mixture (v/v: 9/1) to give thecompound 12 in the form of a white solid (2.9 g; yield of 94%). Itsanalysis by infrared and proton and carbon-13 NMR is as follows.

[0133] IR (dispersion in KBr) ν (cm⁻¹): 3370, 3080, 2917, 2849, 1707,1643.

[0134]¹H NMR (CDCl₃, δ (ppm)): 11.2 (broad s, 1 H), 6.0-5.7 (m, 1 H),5.1-4.7 (m, 2 H), 4.1-4.0 (s, 2 H), 3.6-3.3 (m, 10 H), 2.2-1.9 (m, 2 H)and 1.7-1.0 (m, 36 H).

[0135]¹³C NMR (CDCl₃, δ (ppm)): 172.1, 139.1, 114.0, 71.6-68.7 (5 CH₂),63.5, 33.6-25.8 (19 CH₂).

[0136] Preparation of the Ester 13

[0137] The acid 12 (2.9 g, 6.4 mmol) is dissolved in anhydrous toluene(7 ml) under an inert atmosphere at 0° C. in a 100 ml three-neckedround-bottomed flask. Oxalyl chloride (1.22 g, 9.6 mmol, 1.5 eq) isintroduced dropwise and then the mixture is stirred at ambienttemperature for 2 hours. The excess reactant and the solvent aresubsequently evaporated under vacuum. The acyl chloride is storedtemporarily under argon. Methanol (6 ml, 128 mmol, 20 eq), distilledbeforehand over calcium chloride, is slowly added. The reaction mediumis subsequently brought to reflux for 18 h before being brought back toambient temperature, and then the excess methanol is evaporated. Thereaction medium is then extracted three times with diethyl ether. Theethereal phases are combined and washed with a 10% hydrochloric acidsolution, with water and with a saturated NaHCO₃ solution. The etherealphase is subsequently washed to neutrality, dried over MgSO₄ andconcentrated under vacuum. The compound 13 is obtained in the form of awhite solid and is then purified by silica chromatography (eluent:petroleum ether/ether, 50/50 by volume). 300 mg of a white solid areobtained (yield of 10%). Its analysis by infrared and proton andcarbon-13 NMR is as follows.

[0138] IR (dispersion in KBr) ν (cm⁻¹): 3080, 2917, 2849, 1742, 1643.

[0139]¹H NMR (CDCl₃, δ (ppm)): 6.0-5.7 (m, 1 H), 5.1-4.7 (m, 2 H),4.1-4.0 (s, 2 H), 3.6-3.3 (m, 13 H), 2.2-1.9 (m, 2 H) and 1.7-1.0 (m, 36H).

[0140]¹³C NMR (CDCl₃, δ (ppm)): 171.8, 139.1, 114.0, 71.6-68.7 (5 CH₂),63.6, 51.7, 33.6-25.8 (19 CH₂).

[0141] It is clearly understood that, by using alcohol 8 comprising asingle ethylene glycol unit, the corresponding acids and esters couldalso be obtained according to the same protocols as described herestarting from the alcohol 10.

[0142] 5) Silylation of the Unsaturated Precursors (FIG. 4)

[0143] The ester 9 (150 mg, 0.33 mmol) is introduced into a dry Schlenktube under an inert atmosphere. Freshly distilled trichlorosilane (0.3ml, 2.2 mmol, 6 eq), anhydrous toluene (0.3 ml) and a dropper Kärstedcatalyst (PCO 72), sold by ABCR (reference 68478-92-2), are added. Thereaction medium is then cooled to 40° C. for 2 h. After returning toambient temperature, the toluene and the excess trichlorosilane areevaporated under reduced pressure using a vane pump (pressure is 0.5mmHg). The compound 14 is obtained in the form of a white solid and isstored under argon (yield at 99%). It is an organosilicon compound ofthe formula (I) according to the present invention in which X₁, X₂ andX₃ represent chlorine atoms, n is equal to 22, i is equal to 0, k isequal to 1 and Z represents a —COCH₃ group.

[0144] The analysis of the compound 14 by proton and carbon-13 NMR is asfollows.

[0145]¹H NMR (CDCl₃, δ (ppm)): 4.25-4.15 (m, 2 H), 3.60-3.50 (t, 2 H),3.45-3.35 (t, 2 H), 2.2-1.9 (s, 3 H) and 1.7-1.0 (m, 42 H).

[0146]¹³C NMR (CDCl₃, δ (ppm)): 171.0, 71.5, 68.5, 63.7, 31.9-22.3 (21CH₂), 21.0.

[0147] By starting from the compound 11 obtained above and by using thesame protocol, the corresponding organosilicon compound 15 is obtained.It is an organosilicon compound of formula (I) according to the presentinvention in which X₁, X₂ and X₃ represent chlorine atoms, n is equal to22, i is equal to 0, k is equal to 3 and Z represents the —COCH₃ group.Its analysis by proton and carbon-13 NMR is as follows.

[0148]¹H NMR (CDCl₃, δ (ppm)): 4.3-4.2 (t, 2 H), 3.7-3.4 (m, 10 H),3.4-3.3 (t, 2 H), 2.2-1.9 (s, 3 H) and 1.7-0.9 (m, 42 H).

[0149]¹³C NMR (CDCl₃, δ (ppm)): 171.2, 71.6-68.1 (6 CH₂), 63.6,31.9-22.3 (21 CH₂), 21.0.

[0150] By starting from the compound 13 obtained above and by using thesame protocol, the corresponding organosilicon compound 16 is obtained.It is a compound of formula (I) according to the present invention inwhich X₁, X₂ and X₃ represent chlorine atoms, n is equal to 22, i isequal to 1, k is equal to 2 and Z represents a —COOCH₃ group. Itsanalysis by proton and carbon-13 NMR is as follows.

[0151]¹H NMR (CDCl₃, δ (ppm)): 4.1-4.0 (s, 2 H), 3.6-3.3 (m, 13 H),1.7-0.9 (m, 42 H).

[0152]¹³C NMR (CDCl₃, δ (ppm)): 171.0, 71.6-63.8 (6 CH₂), 51.7,31.9-22.3 (21 CH₂).

EXAMPLE 2 Silanization of a Solid Support Using an OrganosiliconCompound of Formula (I) and Production of an Organized Self-AssembledMonolayer

[0153] 1) Silanization of the Solid Support

[0154] A surface-oxidized silicon disk is used as substrate. The disk iscleaned according to the following procedure, in order to remove thecontaminants from its surface and to hydrate it:

[0155] immersion in a freshly prepared chromium(VI)/sulfuric acidmixture (2.5 g of K₂Cr₂O₄; 2.5 ml of distilled water; 50 ml of sulfuricacid) for 10 minutes,

[0156] under a laminar flow hood equipped with dust filters, the disk isimmersed in deionized water and subjected to ultrasound for 20 minutes.This process is repeated twice with durations of exposure to ultrasoundof 5 and 2 minutes respectively,

[0157] under a laminar flow hood equipped with dust filters, the disk isintroduced into the silanization reactor in order to be dried, under aninert and filtered atmosphere. The reactor is placed for 45 minutes inan oil bath at 100° C., is then removed from the oil bath and itstemperature is brought back to 18° C.

[0158] The organosilicon compound 14 obtained in example 1, freshlyprepared in the desired amount, under an inert atmosphere, is dissolvedin a fraction of a C₆H₁₂/CCl₄/CHCl₃ (v/v/v: 80/12/8) mixture. Theorganosilicon compound 14 in solution is subsequently withdrawn with asyringe and then introduced into a Schlenck tube comprising theremainder of the solvent mixture, the total volume of which has beencalculated to produce a silanization solution of appropriate dilution(between 1×10⁻⁵ and 1×10⁻² mol/liter). The solvents were driedbeforehand according to procedures known per se.

[0159] The salinization solution is introduced, with a syringe, into thereactor and the silicon disk remains immersed in this solution for 16 h.

[0160] The silanized disk is withdrawn from the reactor, is thenimmersed in chloroform (HPLC grade) and is cleaned with ultrasound for 2minutes. This process is subsequently repeated a second time.

[0161] 2) Characterization of the Modified Surface

[0162] A solid support, the surface of which is modified by the compound14, was obtained above. The grafting of the organosilicon compounds ismonitored by using confocal Raman spectroscopy and infraredspectroscopy.

[0163] 3) Release of the Surface Hydroxyls

[0164] If necessary, the surface hydroxyls can be released by using thefollowing protocol: the silanized disk is immersed in a solution of KOH(0.5M) in a water/ethanol (v/v: 1/1) mixture for 20 minutes. The disk issubsequently cleaned with ultrasound for 5 minutes in demineralizedwater. This process is repeated once in water and then a second time inchloroform.

[0165] 4) Characterization of the Surface after Release of the Hydroxyls

[0166] Infrared spectra obtained after three experiments of grafting thecompound 14 to the support according to the protocol given in 1), andafter saponification of the surface esters as indicated above, arerepresented in FIG. 5. The transmission appears on the ordinate and thefrequency (cm⁻¹) on the abscissa. It is noted that the three spectra aresuperimposed, with peaks characteristic of an organized system at 2917and at 2850 cm⁻¹. Thus, it may be concluded therefrom that the graftingof the organosilicon compound to the support is reproducible and givesrise to the formation of an organized self-assembled monolayer.

[0167] Raman spectroscopic studies of the modified surface obtainedabove are represented in FIG. 6. FIG. 6a is representative of thedensity of the surface of the grafted substrate, the dimensions of thesurface appearing on the abscissa and on the ordinate (7 mm in thefigure corresponding to 1 μm in the substrate) and the scale ofdensities being graduated from 130 to 165 (arbitrary units). Thehomogeneity of the surface is demonstrated by this figure. Raman spectrataken at two different points of the surface of the substrate arerepresented in FIGS. 6b and 6 c; the ordinate represents counts persecond and the frequency appears on the abscissa.

[0168] Infrared and Raman spectra therefore unambiguously show ahomogeneity of the film deposited on the substrate and the organizationof the molecules on the surface, characteristic of an organizedself-assembled monolayer. The infrared spectrum also shows that thegrafting of the film is fully reproducible.

EXAMPLE 3 Other Example of Silanization on a Solid Support Using anOrganosilicon Compound of Formula (I)

[0169] The glass microscope slide is used as substrate. The glass slideis cleaned by immersion in a 2% aqueous Hellmanex® solution (sold byPolylabo under the reference 12240) for 2 h at 20° C. and then copiousrinsing with deionized water.

[0170] Under a laminar flow hood equipped with dust filters, the glassslide is introduced into the grafting reactor in order to be dried,under an inert and filtered atmosphere. The reactor is placed for 45minutes in an oil bath at 100° C., is then removed from the oil bath andits temperature is brought back to 18° C.

[0171] The silanization solution, prepared using the organosiliconcompound 14 as indicated in example 2, is introduced, with a syringe,into the reactor and the glass slide remains immersed in this solutionfor 16 h. The silanized substrate is rinsed as described in example 2.

[0172] The characterization of the surface by infrared and Ramanspectroscopy here again demonstrates the production of an organizedself-assembled monolayer on the substrate.

[0173] In addition to that which emerges from the above, the inventionis in no way restricted to those implementations, embodiments andapplication forms which have just been described more explicitly; on thecontrary, it embraces all the alternative forms thereof which can cometo the mind of a technologist in the subject, without departing from thecontext or from the scope of the present invention.

1. An organosilicon compound of formula (I)

in which: n is between 15 and 35, k is between 0 and 100, i is aninteger greater than or equal to 0, X₁, X₂ and X₃, which can beidentical to or different from one another, are selected from the groupconsisting of saturated, linear or branched, C₁ to C₆ alkyls andhydrolyzable groups, at least one from X₁, X₂ or X₃ representing ahydrolyzable group, and if k=0 and i=0, then Z represents an R₁ group,if k=0 and i≧1, then Z represents an —OR₁, —OCOR₁, —NR₁R₂, —COOR₁,—CONR₁R₂ or —SR₁ group or a halogen atom, if k≧1 and i=0, then Zrepresents an —R₁, —COR₁, —COOR₁, —CONR₁R₂, —CF₃ or —(CF₂)_(j)CF₃ group,j being between 1 and 10, if k≧1 and i≧1, then Z represents an —OR₁,—OCOR₁, —NR₁R₂, —COOR₁, —CONR₁R₂, —SR₁, —CF₃ or —(CF₂)_(j)CF₃ group, jbeing as defined above, or a halogen atom, R₁ and R₂, which can beidentical or different, represent a hydrogen atom, an optionallysubstituted, saturated or unsaturated and linear or branchedhydrocarbonaceous chain comprising from 1 to 24 carbon atoms, or anaromatic group, provided that, when k=i=0 and n=15, R₁ is other than the—CH₂CF₃ group and, when k=i=0 and n=19, R₁ is other than the—(CH₂)₆—C≡C—C≡CH group.
 2. The compound as claimed in claim 1,characterized in that said hydrolyzable group is selected from the groupconsisting of halogen atoms, the —N(CH₃)₂ group and —OR groups, R beinga saturated, linear or branched, C₁ to C₆ alkyl group.
 3. The compoundas claimed in claim 1 or claim 2, characterized in that n is between 20and
 25. 4. The compound as claimed in any one of the preceding claims,characterized in that k is between 0 and
 5. 5. The compound as claimedin any one of the preceding claims, characterized in that i is equal to0 or to
 1. 6. The compound as claimed in any one of the precedingclaims, characterized in that X₁, X₂ and X₃ represent chlorine atoms, nis equal to 22, i is equal to 0, k is equal to 1 or to 3 and Zrepresents a —COCH₃ group.
 7. The compound as claimed in any one ofclaims 1 to 5, characterized in that X₁, X₂ and X₃ represent chlorineatoms, n is equal to 22, i is equal to 1, k is equal to 2 and Zrepresents a —COOCH₃ group.
 8. A process for the preparation of thecompound of formula (I) as claimed in any one of claims 1 to 6 in whichi is other than 1, which comprises the following stages: a) preparationof an unsaturated precursor of formula (III)

 by reaction of a diol of formula HO—(CH₂—CH₂—O)_(k)—H with anunsaturated compound of formula (II):

 in which Y represents a nucleofuge group and n and k are as defined inany one of claims 1 to 6; b) production, by functionalization of thehydroxyl end of the compound of formula (III), of an unsaturatedprecursor of formula (IV):

 in which Z and i are as defined in any one of claims 1 to 6; c)production, by hydrosilylation of the unsaturated precursor of formula(IV) using a hydrosilane of formula HSiX₁X₂X₃, of a silicon compound offormula (I):

 in which at least one from X₁, X₂ and X₃ represents a halogen atom; andd) optionally, production of another compound of formula (I) bysubstitution of one or more of the X₁, X₂ and X₃ groups of the compoundobtained in stage c) using X₁, X₂ and/or X₃ groups as defined in any oneof claims 1 to
 6. 9. A process for the preparation of the compound offormula (I) as claimed in any one of claims 1 to 5 and 7 in which i isequal to 1, which comprises the following stages: a) preparation of anunsaturated precursor of formula (III′):

 by reaction of an unsaturated compound of formula (II) as defined inclaim 6 with a diol of formula HO—(CH₂—CH₂—O)_(k+1)—H, n and k being asdefined in any one of claims 1 to 5 and 7; b) production, by oxidationof the hydroxyl end of the compound (III′), of an unsaturated precursorof formula (IV′):

 in which Z represents a carboxylic acid functional group; c)optionally, functionalization of the carboxylic acid end of the compoundof formula (IV′) using another Z group as defined in any one of claims 1to 5 and 7; d) production, by hydrosilylation of the unsaturatedprecursor of formula (IV′) using a hydrosilane of formula HSiX₁X₂X₃, ofa silicon compound of formula (I):

 in which at least one from X₁, X₂ and X₃ represents a halogen atom; ande) optionally, production of another compound of formula (I′) bysubstitution of one or more of the X₁, X₂ and X₃ groups of the compoundobtained in stage d) using X₁, X₂ and/or X₃ groups as defined in any oneof claims 1 to 5 and
 7. 10. The use of a compound of formula (I′):

in which: n is between 15 and 35, k is between 0 and 100, i is aninteger greater than or equal to 0, X₁, X₂ and X₃, which can beidentical to or different from one another, are selected from the groupconsisting of saturated, linear or branched, C₁ to C₆ alkyls andhydrolyzable groups, at least one from X₁, X₂ or X₃ representing ahydrolyzable group, and if k=0 and i=0, then Z represents an R₁ group,if k=0 and i≧1, then Z represents an —OR₁, —OCOR₁, —NR₁R₂, —COOR₁,—CONR₁R₂ or —SR₁ group or a halogen atom, if k≧1 and i=0, then Zrepresents an —R₁, —COR₁, —COOR₁, —CONR₁R₂, —CF₃ or —(CF₂)_(j)CF₃ group,j being between 1 and 10, if k≧1 and i≧1, then Z represents an —OR₁,—OCOR₁, —NR₁R₂, —COOR₁, —CONR₁R₂, —SR₁, —CF₃ or —(CF₂)_(j)CF₃ group, jbeing as defined above, or a halogen atom, R₁ and R₂, which can beidentical or different, represent a hydrogen atom, an optionallysubstituted, saturated or unsaturated and linear or branchedhydrocarbonaceous chain comprising from 1 to 24 carbon atoms, or anaromatic group; it being understood that, when X₁=X₂=X₃=Cl, when k=i=0and when n=19, then R₁ is other than the —(CH₂)₆—C≡C—C≡CH group, toform, at the surface of a solid support, an organized self-assembledmonolayer.
 11. A solid support, the surface of which is modified by anorganized self-assembled monolayer, characterized in that said monolayercomprises a network of at least one organosilicon compound of formula(I′) as defined in claim
 10. 12. The support as claimed in claim 11,characterized in that said solid support is such that its surfaceexhibits, before being modified, hydroxyl groups.
 13. The support asclaimed in claim 12, characterized in that said solid support isselected from the group consisting of glasses, ceramics, metals andsemimetals.
 14. A process for the production of the solid support asclaimed in any one of claims 11 to 13, characterized in that itcomprises the following stages: a) removal of contaminants from a solidsupport and hydration and/or hydroxylation of its surface, b)introduction, under an inert atmosphere, of at least one organosiliconcompound of formula (I′) as defined in claim 10 into a mixture of atleast two solvents comprising at least one nonpolar hydrocarbonaceoussolvent, c) silanization of the support obtained in stage a) byimmersion in the solution prepared in stage b), and d) rinsing of themodified support obtained in stage c) using a solvent.
 15. The processas claimed in claim 14, characterized in that stage a) is carried out,according to the nature of the solid support, using one or more solventsand/or oxidizing agents and/or hydroxylating agents, a detergent or aphotochemical treatment with ozone.
 16. The process as claimed in claim14 or claim 15, characterized in that stage b) is carried out in amixture of at least one nonpolar hydrocarbonaceous solvent and at leastone polar solvent.
 17. The process as claimed in claim 16, characterizedin that the proportions by volume of nonpolar solvent and of polarsolvent are between 70/30 and 95/5.
 18. The process as claimed in anyone of claims 14 to 17, characterized in that the concentration of theorganosilicon compound in the mixture of solvents in stage b) of theprocess is between 1×10⁻⁵ and 1×10⁻² mol/liter.
 19. The use of the solidsupport as claimed in any one of claims 11 to 13 in the synthesis orimmobilization of biomolecules via covalent bonding.
 20. A process forthe synthesis of biomolecules on the solid support as claimed in any oneof claims 11 to 13, characterized in that said biomolecules are composedof a sequence of repeat units and in that said process comprisessuccessive stages of grafting said repeat units, the first graftedrepeat unit carrying a functional group which is reactive with respectto the Z groups of the organosilicon compounds present on the solidsupport.
 21. A process for the immobilization of biomolecules on thesolid support as claimed in any one of claims 11 to 13, characterized inthat it comprises a stage of grafting said biomolecules, which carryfunctional groups which are reactive with respect to the Z groups of theorganosilicon compounds, to said solid support.
 22. The process asclaimed in claim 20 or claim 21, characterized in that it is preceded,in the case where the Z end functional group of the organosiliconcompounds is an —OCOR₁ group in which R₁ is as defined in claim 10 or a—COOR₁ group in which R₁ is as defined in claim 10 and is other than ahydrogen atom, by a stage of deprotection of the corresponding alcoholor carboxylic acid functional group by an appropriate chemicaltreatment.